$\left(-4x - 9\right)\left(9x - 7\right) = \ ?$
$= -4x \cdot \left(9x - 7\right) - 9 \cdot \left(9x - 7\right)$ $= \left( -4x \cdot 9x \right) + \left( -4x \cdot -7 \right) + \left( -9 \cdot 9x \right) + \left( -9 \cdot -7 \right)$ $= -36x^2 + \left( -4x \cdot -7 \right) + \left( -9 \cdot 9x \right) + \left( -9 \cdot -7 \right)$ $= -36x^2 + \left( 28x - 81x \right) + \left( -9 \cdot -7 \right)$ $= -36x^2 - 53x + \left( -9 \cdot -7 \right)$ $= -36x^2 - 53x + 63$